Fuel dispensers at service stations usually contain fuel filters within each dispensing unit. These fuel filters are similar to oil filters on an automobile, as the filter is contained within a canister which is threaded onto an in-line connector. The internal filter must be changed regularly which requires removal of the canister from the in-line connector. Similar to the experience of changing an oil filter, unscrewing the canister for the fuel filter allows fuel to spill from the in-line connector. If not maintained in a perfectly vertical orientation during removal, fuel will also spill from the canister.
Since service stations typically have multiple dispensing units, these spills may add up to a considerable loss of fuel. This is not only an economical loss to the station but is also an environmental concern. The spilled fuel may contaminate the soil or the surrounding surfaces, and the evaporation of the fuel will contaminate the atmosphere.
It appears that California has already enacted relevant environmental protection laws, and it is anticipated that other states will also be passing laws concerning the loss of volatile fuels through vaporization. Thus, there is a need for a way to prevent the loss of volatile fuels and other contaminants during the replacement of in-line filters.